1. Technical Field
This application relates to sound processing and, more particularly, to adaptive equalization of speech signals.
2. Related Art
A speech signal may be adversely impacted by acoustical or electrical characteristics of the acoustical environment or the electrical audio path associated with the speech signal. For example, for a hands-free telephone system in an automobile, the in-car acoustics or microphone characteristics may have a significant detrimental impact on the sound quality or intelligibility of a speech signal transmitted to a remote party.
Many speech enhancement systems have been developed to suppress background noise and improve speech quality, but little progress has been made to improve speech intelligibility. In recent years, researchers have investigated why current speech enhancement algorithms do not improve speech intelligibility. As a result, new algorithms have been developed that focus on speech intelligibility improvement. However, some of these algorithms require a voicing decision, which may be difficult to achieve in a noisy environment. Other proposed algorithms need additional training, or they need to know the clean speech and noise level in advance, which may not be possible in some applications.